In many industries, a vertical centrifugal pump system is employed. This type a pump system normally includes a centrifugal pump casing at the bottom of the system, an electric motor at the top, and a bearing assembly intermediate to and vertically connecting the motor and the pump. To repair the bearing assembly and/or impeller of the pump, it is necessary to remove the bearing assembly from the pump system. This removal can be accomplished by first removing the electric motor and then removing the bearing assembly. Removing and reinstalling the electric motor, however, significantly lengthens the time necessary to service the bearing assembly because the electric motor must be carefully reinstalled so that the axis of the electric motor is properly aligned with the axis of the pump. This reinstallation is frequently a trial and error technique whereby shims are placed under the flange of the motor mount and the shaft is measured for alignment. A second disadvantage of this method is that removal of the electric motor will typically require the services of an electrician in addition to the pump mechanic, which increases the repair expense and poses a scheduling problem for the servicing of the bearing assembly. A third disadvantage of this method is failure to disconnect the electric motor from power supply presents a potential for injury due to an inadvertent starting of the motor or a shock hazard.
Because of the above considerations, the best method for removal and replacement of the bearing assembly is a method which would allow the bearing assembly to be horizontally or laterally removed from the pump system. To allow this horizontal movement, however, the impeller which is attached to the bottom part of the bearing assembly must clear the top of the pump casing. If there is insufficient clearance between the top end of the bearing assembly shaft and the bottom end of the electric motor shaft to allow the impeller to clear the pump casing, it is necessary to pivot or rotate the bearing assembly. A typical bearing assembly, however, is bulky and has a substantial weight. Therefore, a mechanic must employ mechanical means to accomplish this lifting and rotation of the bearing assembly. However, because of the substantial weight, this lifting and rotation poses a safety issue to the personnel involved. In addition the bearing assembly can be damaged during removal or installation if not handled properly.
In the typical work environment where these vertical pump systems are found, the most available mechanical means for servicing the pump systems include overhead cranes, "cherry pickers", forklifts and tripods with chain hoists. As these devices can only lift in a vertical direction, they lack the ability to lift and pivot or rotate the bearing assembly without removal of the electric motor.